Ultrasonic synthesis and spectral characterization of a new blue fluorescent dendrimer as highly selective chemosensor for Fe3+ cations

Sensing and Microbiological Activity of a New Blue Fluorescence Polyamidoamine Dendrimer Modified with 1,8-Naphthalimide Units

A novel second-generation blue fluorescent polyamidoamine dendrimer peripherally modified with sixteen 4-N,N-dimethylaninoethyloxy-1,8-naphthalimide units was synthesized. Its basic photophysical characteristics were investigated in organic solvents of different polarity. It was found that in these solvents, the dendrimer is colorless and emitted blue fluorescence with different intensities depending on their polarity. The effect of the pH of the medium on the fluorescence intensity was investigated and it was found that in the acidic medium, the fluorescence is intense and is quenched in the alkaline medium. The ability of the dendrimer to detect metal ions (Pb2+, Zn2+, Mg2+, Sn2+, Ba2+, Ni2+, Sn2+, Mn2+, Co2+, Fe3+, and Al3+) was also investigated, and it was found that in the presence of Fe3+, the fluorescent intensity was amplified more than 66 times. The antimicrobial activity of the new compound has been tested in vitro against Gram-positive B. cereus and Gram-negative P. aeruginosa. The tests were performed in the dark and after irradiation with visible light. The antimicrobial activity of the compound enhanced after light irradiation and B. cereus was found slightly more sensitive than P. aeruginosa. The increase in antimicrobial activity after light irradiation is due to the generation of singlet oxygen particles, which attack bacterial cell membranes.

Highly selective silica-based fluorescent nanosensor for ferric ion (Fe3+) detection in aqueous media

A highly selective fluorescence nanosensor was built based on the functionalized SBA-15 mesoporous silica with Dinitrophenylhydrazine (DNPH). The interaction of fabricated nanosensor was studied with metals ions in aqueous media. Under optimum conditions (time 5min, pH7, sensor dose 0.02g dispersed in 1L), SBA-15-DNPH was highly selective toward the Fe³⁺ ion in the presence of the different groups of interfering metal ions. The detection limit and linear concentration range of the nanosensor were 39×10^-6M and 5×10^-5-375×10^-5M; respectively. The efficiency of nanosensor was independent on the pH range studied (6-9), which indicated that SBA-15-DNPH is a promising candidate for sensing and identification of Fe³⁺ ion in the environmental and other real matrix samples. SBA-15-DNPH showed good performance for Fe³⁺ ion detection and quantification in real samples.

Diphenylether based derivatives as Fe(iii) chemosensors: spectrofluorimetry, electrochemical and theoretical studies

Differential pulse voltammetric studies on DPE-I and DPE-II indicating selective response to Fe³⁺, supported by DFT studies using Gaussian software.

A highly selective fluorescent sensor for Fe3+ based on covalently immobilized derivative of naphthalimide

In this paper, the fabrication and analytical characteristics of fluorescence-based ferric ion-sensing glass slides were described. To fabricate the sensor, a naphthalimide derivative (compound 1) with a terminal double bond was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) on the activated surface of glass slides by UV irradiation. Upon the addition of Fe(3+) in 0.05 mol/L Tris/HCl (pH 6.02) at 25 °C, the fluorescence intensity of the resulting optical sensor decrease, which has been utilized as the basis for the selective detection of Fe(3+). The sensor can be applied to the quantification of Fe(3+) with a linear range covering form 1.0×10(-5) to 1.0×10(-3) M and a detection limit of 4.5×10(-6) M. The experiment results show that the response behavior of the sensor to Fe(3+) is pH-independent in medium condition (pH 5.00-8.00) and exhibits high selectivity for Fe(3+) over a large number of cations such as alkali, alkaline earth and transitional metal ions. Moreover, satisfactory reproducibility, reversibility and a rapid response were realized. The sensing membrane was found to have a lifetime at least 2 months. The accuracy and the precision of the method were evaluated by the analysis of the standard reference material, iron in water (1.0 mol/L HNO3). The developed sensor is applied for the determination of iron in pharmaceutical preparation samples with satisfactory results.

Detection of Metal Ions and Protons with a New Blue Fluorescent Bis(1,8-Naphthalimide)

The synthesis of a new blue fluorescent bis(1,8-naphthalimide) has been described and its basic photophysical characteristics have been investigated in organic solvents of different polarity. The detection of protons and different metal cations (Ag+, Cu2+, Co2+, Ni2+, Fe3+ and Zn2+) with the new compound has been investigated by the use fluorescence spectroscopy.

Iron(III) selective molecular and supramolecular fluorescent probes

Iron is one of the most important elements in metabolic processes, being indispensable for all living systems and therefore it is extensively distributed in environmental and biological materials. However, both its deficiency and excess from the normal permissible limit can induce serious disorders. Therefore, several analytical techniques have been adopted for the detection of iron. Among the various techniques used for its detection, the method based on fluorescent sensors has received considerable interest in recent years because of its ability to provide online monitoring of very low concentrations without any pre-treatment of the sample together with the advantages of spatial and temporal resolution. In this article, efforts have been made to review the various molecular and supramolecular fluorescent sensors that have been developed for the selective detection of iron(III).